Down Survey

The Down Survey was a cadastral survey of Ireland, carried out by English scientist, William Petty, in 1655 and 1656. It was created to provide for precise re-allocation of land confiscated from the Irish.

The survey was apparently called the "Down Survey" by Petty, either because the results were set down in maps or because the surveyors made use of Gunther's chain, which had to be "laid down" with every measure. At the time of its creation, it was considered one of the most accurate maps, and the first British imperial survey of an entire conquered nation.